Basic design exercise: design a system to replace their indexing service which collects data from micro-services and feeds it into SOLR (future: Elastic Search because reportedly Solr indexes go bad & don't support re-indexing) - feed any updates to relevant data stores quickly into SOLR / Elastic Search - include process (re-indexing service / logic) to collect all xx million records from micro-services and feed into SOLR / ES - what is the "data contract" for a micro-service to support the re-index process